Eochocán mac Áedo (died 883) was a Dál Fiatach king of Ulaid, which is now Ulster, Ireland.
He was the grandson of Eochaid mac Fiachnai (died 810), a previous king of Ulaid.
In 882 he succeeded his brother Ainbíth mac Áedo as leth-rí (half-king or co-ruler) of Ulaid jointly with his other brother, Airemón mac Áedo (died 886).
However, the next year in 883, Eochocán was killed by his nephews, the sons of Ainbíth.
[3] He had married Inderb ingen Máel Dúin of the Cenél nEógain, daughter of Máel Dúin mac Áeda, King of Ailech (died 867).